There are a variety of abnormal conditions in the human or animal body which are limited to the internal linings of the hollow organs. Colonic polyps, intestinal arteriovenous malformations, endothelial vascular lesions, abnormal venous valves, and complicated internal hemorrhoids are just few examples. Other conditions may involve the full thickness of the wall of the hollow organ as in a colonic perforation, an invading malignant tumor, etc. An endoluminal approach to such abnormal conditions may be highly beneficial to the patient since a surgical access trauma is essentially eliminated.
One common condition that is relatively easily treated using an endoluminal approach are complex hemorrhoids. These are traditionally treated utilizing a variety of interventional and non-interventional endoluminal methods. An immediate proximity of internal hemorrhoids to the external orifice allows for a fairly easy access. Several technologies are available on the market and are reviewed below. They, however, carry well-known limitations related to cost, technical complexity and/or poor clinical outcomes.
Hemorrhoidal disease is a very common condition, affecting more than half of people at age 50. Approximately 500,000 patients receive one or another type of interventional treatment annually in the United States for symptomatic hemorrhoids. Approximately 160,000 patients a year in the U.S. undergo surgical excision of hemorrhoids.
The term “hemorrhoid” is generally used to refer to the disturbing perianal symptoms related to vascular complexes in the lower rectum and anus. This is usually associated with enlargement of this naturally occurring vascular tissue, which is responsible for its subsequent bleeding, prolapsing, thrombosis, itching, burning, etcetera. The word “hemorrhoids” originates from Greek “haimorrhoos” (haimo-hemo+rhein-to flow), which means “flowing with blood.” The word “pile” is a synonym for hemorrhoid, which originates from Latin “pila”-“ball.”
Repetitive straining due to constipation appears to be a leading factor in forming and progressing of hemorrhoids. The chances of having symptomatic hemorrhoids increase with age, pregnancy, obesity, sedimentary life, heavy lifting and genetic predisposition.
The rectum is arbitrarily separated from the anus by the so-called dentate line. Rectal mucosa is free of pain receptors. The procedures limited to the rectal mucosa, therefore, generally are not associated with pain. In contrast, anal mucosa contains many pain receptors and is, therefore, very sensitive to painful stimuli. Hemorrhoids, located in the rectum, are called internal. Internal hemorrhoids are located within the submucosal layer. External hemorrhoids are located in the anus. Internal and external hemorrhoids have generally different clinical presentation and complications. Internal hemorrhoids are prone to bleeding and prolapsing outside of the anal ring. A prolapsed internal hemorrhoid can easily become traumatized and strangulated by a spastic anal sphincter. External hemorrhoids may rupture, causing painful subcutaneous lumps in the perianal area, which is frequently referred to as “thrombosed external hemorrhoids”. Thrombosis of external hemorrhoid may lead to ulceration of the overlying tissues and bleeding. Both types of hemorrhoids may be responsible for perianal discomfort, itching, irritation, impeding of perianal hygiene, loss of work time and measurable decrease of quality of life.
Treatment is tailored to the type and severity of hemorrhoids. Pharmacological treatment, which is aimed at the regulation of defecation and symptomatic relief, is notorious for having only temporary and frequently incomplete effect. Current interventional, non-excisional, therapies are designed to obliterate blood supply to part of or to the entire hemorrhoid (rubber band ligation, infrared coagulation, injection sclerotherapy, ultrasound guided hemorrhoidal artery ligation). These have modest, inconsistent clinical success with frequent recurrences.
Rubber band ligation is the most popular method of treatment of hemorrhoids in the United States. The technique was described by Blaisdell in 1963. It is quick and not expensive. In this procedure, some hemorrhoidal tissue is pulled into the ligator and a rubber band is placed around the base of the pulled tissue. This causes essentially a strangulation of the blood supply to a portion of the internal hemorrhoid and its overlying rectal mucosa. An ischemic necrosis and autoamputation of the hemorrhoid follows in a few days, leaving an open rectal wound, which heals over several days. Significant postprocedural pain, affecting daily routine, is rare and is probably related to the placement of the band too close to the dentate line (pain-sensitive area). Although rubber band ligation is very effective for immediate bleeding control of small internal hemorrhoids, frequently several treatments of a single larger hemorrhoid are required in order to achieve substantial size reduction. Since the significant portion of the hemorrhoid is usually not removed, recurrences are frequent. In addition, since this treatment leaves the patient with an open wound in the anus for several days or weeks, rubber band ligation might be rendered unsuitable for HIV-positive patients and requires demanding preparation for patients with inherited, acquired and iatrogenic coagulopathy.
Sclerotherapy is another method to treat first- and second-degree internal hemorrhoids. The delivery of a sclerosing agent is accomplished through a single fine needle, attached to the syringe, and is intended to be within the vascular lumen. Since a hemorrhoid is essentially a ball of multiple twisted vascular lumens, it is virtually impossible to deliver sclerosing agent with the desired precision. The rates of complications and recurrence are high.
Ultrasound guided hemorrhoidal artery ligation involves manual suturing of the rectal tissues containing the hemorrhoial artery. The artery is located by the ultrasound. A resulting regression of the corresponding internal hemorrhoid is expected. Since suture-ligation is performed above the internal hemorrhoid in the pain-insensitive zone, the procedure should be painless. The technique is demanding and is highly dependent on the operator's experience and dexterity. Inexperience or lack of skill is responsible for both “missing” the hemorrhoidal artery and inadvertent rectal and vascular injuries. Hemorrhoidal artery injuries with resulting severe bleeding, rectal wall injury, etc. have been reported. Recurrences are frequent.
Infrared coagulation of a hemorrhoidal artery involves delivery of the infrared coagulation energy to the hemorrhoidal artery and causes subsequent regression of the corresponding internal hemorrhoid. Since the exact location of the artery is not known and is only presumed to be just proximal to the internal hemorrhoid, several blind infrared firings are required to improve the chance of reaching the hidden target. Several sessions of treatments in a time span of several weeks is recommended. The proper application of the infrared probe is more difficult with larger hemorrhoids due to obscurity of the interface between the probe and mucosa. Recurrences are frequent.
None of the above described techniques adequately addresses tissue redundancy and tissue prolapse, which frequently accompany more advanced stages (late 2nd, 3rd and 4th) of hemorrhoidal disease and, therefore, can be considered only for the treatment of 1st and early 2nd stages of internal hemorrhoids. Even then, the rate of recurrence is substantial, reflecting the deficiencies of the existing methods.
The only approach which has been found to be consistently effective in the long-lasting control of the hemorrhoidal symptoms is the surgical excision of the hemorrhoids. There are two main methods of surgical excision of internal hemorrhoids: traditional surgical excision (longitudinal hemorrhoidectomy) and the so-called Procedure for Prolapse and Hemorrhoids or PPH (transverse hemorrhoidectomy with circular stapler).
Traditional surgical excision of hemorrhoids is a very effective but debilitating form of treatment. The hemorrhoidal tissue essentially is removed in longitudinal fashion down to the underlying internal sphincter. Traditional surgical excision almost invariably extends the anal trauma to and beyond the dentate line, thus causing severe postoperative pain. The technique is highly dependent on the technical skill of the operator. Surgical excision of hemorrhoids requires anesthesia and causes severe perianal pain for several weeks and significant loss of work time.
The so-called Procedure for Prolapse and Hemorrhoids (PPH) involves circumferential excision of the rectal mucosa and submucosal layer with a circular stapler, proximal to the internal hemorrhoids. The procedure is essentially directed towards a radical devascularization of the hemorrhoids while the hemorrhoidal tissue itself is left to ischemically regress. Since excision is done in the pain insensitive area (above the dentate line), a decreased postoperative pain and faster recovery when compared to traditional hemorrhoidectomy are observed. The internal hemorrhoids purportedly shrink within four to six weeks after the procedure. Advocates of PPH claim less pain and faster recovery, but the technique requires anesthesia and a demanding technical and instrumental set-up. In addition, this technique creates substantial circumferential rectal trauma, which is clearly excessive in the majority of cases when only 1 or 2 hemorrhoids are enlarged. Serious complications have been reported. A substantial circumferential injury of the anal canal and subsequent scarring may cause rectal stricture (narrowing), which is debilitating and difficult to treat. The technique requires massive anal dilation in order to accommodate a large head assembly of the circular stapler, which by itself presents an additional source of postoperative anal discomfort and potential anal trauma (anal fissures, bleeding, etc.). The main achievement of PPH technique over traditional hemorrhoidectomy is the placement of the surgical injury line in transverse fashion above the dentate line.
In summary, although many minimally invasive techniques have been introduced to treat symptomatic internal hemorrhoids, these entail a high rate of recurrence and a need for repetitive procedures. Approximately 15-20% of patients undergoing an intervention for treatment of their internal hemorrhoids require surgical excision of hemorrhoids, mainly because the current non-excisional techniques do not address or address inadequately (rubber band ligation) the accompanying anal mucosal prolapse and tissue redundancy. Some groups of patients, such as HIV-positive patients, and patients with spinal cord injuries, coagulopathy, etc, have absolute or relative contraindications to the existing techniques. The Procedure for Prolapse and Hemorrhoids addresses many of the deficiencies of the existing techniques, but involves a demanding technical and instrumental set-up, requires general or regional anesthesia, and is designed to perform frequently unnecessary circumferential rectal injury.
There is a need, therefore, for a device which allows fast and effective treatment of hemorrhoids in minimally invasive (innocent tissues are spared) and painless fashion (excisional line is placed above the dentate line).